DMRC Electronics Engineering Paper-1 2016

n

$$\frac{1}{n}$$

$$n^2$$

$$\frac{1}{n^2}$$

Zero

110 V

220 V

440 V

ADC

DAC

Comparator

555 timer

Same as that of the modulating signal bandwidth

Twice of modulating signal Bandwidth

Thrice as of modulating signal Bandwidth

Infinite

They depend on straight-line propagation which applies to microwaves only

Losses would be too heavy at lower frequencies

There are no generators powerful enough to excite them at lower frequencies

They would be too bulky at lower frequencies

Better noise immunity is provided

Lower bandwidth is required

The transmitted power is more useful

Less modulating power is required

Reduce the bandwidth used

Separate differing transmissions

Ensure that intelligence may be transmitted over long distances

Allow the use of practicable antennas

Remains unaltered

Moves towards the conduction band

Move towards the center of forbidden energy gap

May or may not move depending on temperature

A random signal with flat power spectral density

A random signal generated by beat signal

A random signal with long range correlation

All of the above are true

$$\overline{A + B} = \overline{A} . \overline{B}$$

$$\overline{A + B} = A.B$$

$$\overline{A + B} = \overline{A} . \overline{B} + A.B$$

$$\overline{A + B} = \overline{A} . B$$